Recording tape cartridge

Abstract

A recording tape cartridge includes: a case accommodating a reel on which a recording tape is wound; a brake member provided non-rotatably with respect to the case; a lock member provided in a mounting portion on the inner surface of a top plate of the case to be slidable in a radial direction of the reel; and a falling-out preventing member for keeping the lock member from being removed from the mounting portion. The brake member is arranged to selectively assume a rotation locking position where the brake member is engaged with the reel to prevent the reel from being rotated and a rotation permitting position where the brake member is disengaged from the reel to permit the reel to be rotated. The lock member is arranged, when the brake member assumes the rotation locking position, to be interposed between the upper surface of the reel and a top plate of the case, thereby preventing the reel from being moved axially thereof. The lock member is also arranged, when the brake member is moved from the rotation locking position to the rotation permitting position, to be removed from between the upper surface of the reel and the top plate of the case in response to the movement of the brake member, thereby permitting the reel to be moved axially thereof. When the brake member assumes the rotation locking position, a clearance is defined between the lock member and the brake member, and the clearance is made smaller than the movement stroke of the brake member from the rotation locking position to the rotation permitting position.

1. A recording tape cartridge, comprising:
 a case for accommodating a reel on which a recording tape is wound; 
 a brake member provided non-rotatably with respect to the case, the brake member being capable of being moved to selectively assume a rotation locking position where the brake member is disposed in engagement with the reel thereby preventing the reel from being rotated and a rotation permitting position where the brake member is disposed out of engagement with the reel thereby permitting the reel to be rotated; 
 an engagement projection provided on the brake member, the engagement projection having a first tapered surface formed on an end portion thereof; 
 a lock member provided in a mounting portion formed on an inner surface of a top plate of the case, the lock member being slidable in a radial direction of the reel, the lock member being arranged, when the brake member assumes the rotation locking position, to be interposed between an upper surface of the reel and the top plate of the case thereby preventing the reel from being moved axially, lock member being also arranged, when the brake member is moved to assume the rotation permitting position, to be removed from between the upper surface of the reel and the top plate of the case in interlocking relationship with the movement for the brake member to assume the rotation permitting position thereby permitting the reel to be moved axially; 
 a cam portion provided on the lock member, the cam portion being engageable with the engagement projection and having a second tapered surface formed on an end thereof; 
 a stabilizing portion provided on the lock member more inward than the cam portion in a radial direction of the reel, 
 a falling-out preventing member for preventing the lock member from falling out from the mounting portion; 
 wherein a clearance between the first tapered surface and the second tapered surface at the rotation locking position in a direction of the movement of the brake member is made shorter than a length of movement stroke of the brake member from the rotation locking position to the rotation permitting position; 
 wherein a reactive force against a torque imparted to the lock member when the first tapered surface contacts the second tapered surface is produced by the stabilizing portion and the falling-out preventing member. 
 
     
     
       2. The recording tape cartridge according to  claim 1  wherein an angle between the engagement projection and the second tapered surface of the cam portion is in a range from 30 degrees to 60 degrees. 
     
     
       3. The recording tape cartridge according to  claim 1  further comprising:
 a first elastic member provided between the brake member and the mounting portion for permitting the brake member to selectively assume the rotation locking position and the rotation permitting position; and 
 a second elastic member provided between the lock member and the mounting portion for permitting the lock member to slide in a radial direction of the reel in response to the movement of the brake member. 
 
     
     
       4. The recording tape cartridge according to  claim 3  wherein the first elastic member comprises a compression coil spring. 
     
     
       5. The recording tape cartridge according to  claim 4  wherein the compression coil spring is contacted at a first end with the falling-out preventing member and at a second end with the brake member. 
     
     
       6. The recording tape cartridge according to  claim 3  wherein the second elastic member comprises a leaf spring. 
     
     
       7. The recording tape cartridge according to  claim 6  wherein: the brake member includes an engagement projection; the lock member includes a cam portion engageable with the engagement projection; and the leaf spring is mounted substantially at a center of the mounting portion and contacted with a radially inner surface of the cam portion of the lock member. 
     
     
       8. The recording tape cartridge according to  claim 7  wherein the leaf spring is attached to a crimping pin projectingly provided substantially at a center of the mounting portion. 
     
     
       9. The recording tape cartridge according to  claim 7  wherein the inner surface of the cam portion is inclined at a predetermined angle thereby causing a biasing force of the leaf spring to be directed toward the top plate of the case. 
     
     
       10. The recording tape cartridge according to  claim 7  wherein an outside surface of the cam portion and a contacting inside surface of the engagement projection are formed with a mold draft angle substantially equal to zero degrees. 
     
     
       11. The recording tape cartridge according to  claim 3  wherein the second elastic member comprises a coil spring. 
     
     
       12. The recording tape cartridge according to  claim 3  wherein the second elastic member comprises a plurality of coil springs. 
     
     
       13. The recording tape cartridge according to  claim 11  wherein the coil spring is provided between a retainer projection provided substantially at a center of the mounting portion and a radially inside surface of a cam portion provided on the lock member. 
     
     
       14. The recording tape cartridge according to  claim 13  wherein the coil spring is fitted over a fitting portion provided on a radially inside surface of the cam portion. 
     
     
       15. The recording tape cartridge according to  claim 14  wherein the fitting portion is cross-shaped in section and has an outer diameter slightly larger than an inner diameter of the coil spring. 
     
     
       16. The recording tape cartridge according to  claim 14  wherein the inside surface of the cam portion is provided with an end portion slightly longer than the fitting portion. 
     
     
       17. The recording tape cartridge according to  claim 13  wherein the retainer projection includes a pair of inwardly projecting retainer claws for retaining one end of the coil spring from both sides. 
     
     
       18. A recording tape cartridge, comprising:
 a case for accommodating a reel on which a recording tape is wound on a reel hub including an upper flange and a lower flange; 
 a brake member being provided non-rotatably with respect to the case, the brake member being capable of being moved to selectively assume a rotation locking position where the brake member is disposed in engagement with the reel thereby preventing the reel from being rotated and a rotation permitting position where the brake member is disposed out of engagement with the reel thereby permitting the reel to be rotated; 
 an engagement projection provided on the brake member, the engagement projection having a first tapered surface formed on an end portion thereof; 
 a lock member provided in a mounting portion formed on an inner surface of a top plate of the case, the lock member being slidable in a radial direction of the reel, the lock member being arranged, when the brake member assumes the rotation locking position, to be interposed between an upper surface of the reel and the top plate of the case thereby preventing the reel from being moved axially, the lock member being also arranged, when the brake member is moved to assume the rotation permitting position, to be removed from between the upper surface of the reel and the top plate of the case in interlocking relationship with the movement of the brake member to assume the rotation permitting position thereby permitting the reel to be moved axially; 
 a cam portion provided on the lock member, the cam portion being engageable with the engagement projection and having a second tapered surface formed on an end portion thereof; 
 a stabilizing portion provided on the lock member more inward than the cam portion in a radial direction of the reel; 
 a first elastic member provided between the brake member and the mounting portion for permitting the brake member to selectively assume the rotation locking position and the rotation permitting position; 
 a second elastic member provided between the lock member and the mounting portion for permitting the lock member to slide in a radial direction of the reel in response to the movement of the brake member, and 
 a falling-out preventing member for preventing the lock member from being removed from the mounting portion; 
 wherein a clearance between the first tapered surface and the second tapered surface at the rotation locking position in a direction of the movement of the brake member is made shorter than a length of movement stroke of the brake member from the rotation locking position to the rotation permitting position; 
 wherein a thickness of a portion of the lock member which is interposed between an upper surface of the reel and the top plate when the brake member assumes the rotation locking position is made substantially equal to a distance between the upper flange and the top plate; and 
 wherein a reactive force against a torque imparted to the lock member when the first tapered surface contacts the second tapered surface is produced by the stabilizing portion and the falling-out preventing member. 
 
     
     
       19. The recording tape cartridge according to  claim 1  wherein a plurality of the lock members are provided. 
     
     
       20. The recording tape cartridge according to  claim 18  wherein a plurality of the lock members are provided.